Analog Devices,inc.

Analog Devices Global

Analog Devices Global Unlimited Company

Joseph Bradford Brannon

Patrick Joseph Pratt

Ronald Dale Turner

David H Robertson

Carroll Clifton Speir

James C Camp

Guanghua Man

Ronald D Turner

An envelope tracking scheme can be used, such as to modulate a supply node of a power amplifier circuit to improve efficiency. For example, a magnitude or amplitude envelope of a signal to be modulated can be scaled and used to drive a node, such as a drain, of the power amplifier circuit. An envelope tracking signal can be generated such as having a bandwidth that is compressed as compared to a full-bandwidth envelope signal. A peak-value 'look ahead' technique can be used, for example, so that amplitude compression or clipping of the transmit signal is suppressed when the bandwidth-compressed envelope tracking signal is used to modulate a supply node of the power amplifier used to amplify the transmit signal.

Broadband envelope tracking

Aspects of this disclosure relate to a receiver for digital predistortion (DPD). The receiver includes an analog-to-digital converter (ADC) having a sampling rate that is lower than a signal bandwidth of an output of a circuit having an input that is predistorted by DPD. DPD can be updated based on feedback from the receiver. According to certain embodiments, the receiver can be a narrowband receiver configured to observe sub-bands of the signal bandwidth. In some other embodiments, the receiver can include a sub-Nyquist ADC.

Receivers for digital predistortion

In an example, there is disclosed a multiple-input analog-to-digital converter configured to receive a plurality of analog inputs and to output one or more digital outputs. In one embodiment, two input analog signals are received. The two analog signals may be mixed in a combiner, which provides them to a pipeline ADC. In another embodiment, the combiner may time multiplex the two analog input signals and provide two separate outputs signals. Advantageously, the multiple-input ADC of the present Specification may be realized with a single ADC pipeline.

Multi-input analog-to-digital converter

Embodiments of the present invention may provide a signal processing circuit that may comprises an analog-to-digital converter (ADC), and an output restriction circuit. The output restriction circuit may reduce the accuracy of the digital output of the ADC when signal content exceeds a pre-determined spectrum mask in an undesirable band. In one embodiment, the input signal spectrum may be actively monitored and when the input spectrum is inconsistent with an intended application, the output resolution may be restricted, for example, by truncating least significant bits (LSBs) of the digital output or adding digital noise.

Growing community of inventors

Greensboro, NC, United States of America

Joseph Bradford Brannon